# Cellular and Molecular Mechanisms of Regulatory T Cells in EAE

> **NIH NIH R01** · UNIVERSITY OF CALIFORNIA-IRVINE · 2020 · $498,868

## Abstract

PROJECT SUMMARY/ABSTRACT
Multiple sclerosis (MS) and other autoimmune diseases constitute a major healthcare burden at a cost of
>$50 billion per year. Autoimmunity arises from a failure of immunoregulation, in which regulatory T
cells (Tregs) play a crucial role in balancing immune responses, though their suppressive mechanisms
are incompletely understood and little is known about their cellular dynamics. Our overall goal is to
identify cellular and molecular immunoregulatory mechanisms that contribute to disease progression
and response to therapy. Building on our expertise in two-photon (2-P) imaging at the cellular level,
and Ca2+ signaling at the molecular level, we will use the experimental autoimmune encephalomyelitis
(EAE) mouse model of MS to investigate cellular interactions and molecular mechanisms underlying
disease progression, as well as therapeutic approaches to promote remission. We focus in particular on
Tregs, which maintain homeostasis and limit autoimmunity. Our central hypothesis is that Tregs limit
autoimmune-mediated demyelination in the EAE model at two levels. (i) At the cellular level, Tregs
compete with conventional T cells for access to antigen-presenting dendritic cells (DCs), and restrict
egress of differentiated, pathogenic effector T cells (Teffs) from lymph nodes (LN). In Aim 1, we will
apply simultaneous 2-P imaging of Tregs, naïve T cells, Teffs, and DCs in the LN to reveal fundamental
cell trafficking and interaction dynamics during EAE induction, progression, and remission. Aim 2
extends those studies to the spinal cord where, by additionally imaging oligodendrocytes and neuronal
cells, we will elucidate the cellular dynamics of neuroinflammation and demyelination during disease
progression and remission. In both Aims, we further propose to define cellular dynamics during
therapies that show great promise for treating MS in humans including drugs that target S1P1 receptors
to cause lymphocyte sequestration within the LN, and stem cell therapy to promote remyelination. (ii)
At the molecular level, Tregs directly contact target lymphocytes to inhibit Ca2+ signaling and suppress
their activation. We have previously shown that Ca2+ signaling in T cells is mediated by plasma
membrane Orai1 channels and triggered by STIM1 in the endoplasmic reticulum. In Aim 3, we propose
to investigate the roles of these proteins employing a novel `toolkit' of genetically-encoded Ca2+
indicators and probes of channel function to monitor cellular Ca2+ signaling in LN and spinal cord. We
hypothesize that Treg contact with naïve or effector T cells results in dissolution of Orai1 puncta and
transendocytosis of Orai1 channel protein into Tregs. We will evaluate Orai1 as a therapeutic target in
MS by visualizing cellular dynamics following administration of a specific Orai1 blocker during EAE
and the translational potential of this approach will be validated with human cells. Although this
proposal is targeted specifically to MS, our fi...

## Key facts

- **NIH application ID:** 9850853
- **Project number:** 5R01AI121945-05
- **Recipient organization:** UNIVERSITY OF CALIFORNIA-IRVINE
- **Principal Investigator:** MICHAEL D CAHALAN
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $498,868
- **Award type:** 5
- **Project period:** 2016-06-20 → 2021-01-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9850853

## Citation

> US National Institutes of Health, RePORTER application 9850853, Cellular and Molecular Mechanisms of Regulatory T Cells in EAE (5R01AI121945-05). Retrieved via AI Analytics 2026-05-22 from https://api.ai-analytics.org/grant/nih/9850853. Licensed CC0.

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